1. Field of the Disclosure
The present invention concerns the field of manufacture of one-piece modular tool holders or others used in multi-spindle, multi-post machines, for the precisely identical mounting of tools on such machines, and has as its object an axially adjustable tool holder.
2. Background Art
Axial adjustment of tools is generally done by means of adjustment sleeves mounted in the tool holders.
Tools used on multi-spindle machines machining identical parts at the same time require particularly precise axial adjustment of tools, in order to strictly respect the operations of the different parts, that is, milling, boring, dressing, peripheral milling, etc.
In such machines, each tool must be perfectly pre-adjusted in length and in a strictly identical manner from one spindle to another, that is, with the same precision.
For this purpose, FR-A-2 590 819 proposed such a device, essentially constituted by an attachment provided with a nose for mounting in machine spindles of the standard American taper, Morse taper, cylindrical shank type or others, and housing, in its extremity opposite the nose, a mobile part of the monobloc or modular type for reception of a tool. In this device, the housing for reception of the mobile part of the attachment is in the form of two bores of differing diameters, the larger of which extends from the face of the attachment and is connected to the smaller in the interior of said attachment, these bores presenting a length so as to permit longitudinal centering of the mobile piece. In addition, the attachment is provided at the level of the larger bore, on one hand with at least two screws for locking and adjustment of the mobile part cooperating with reversed, inclined, spherical grooves on the mobile part and, on the other, with at least one guiding element projecting into one of the bores and cooperating with a corresponding groove of the mobile part.
This device permits significant improvement in precision of mounting, but it is relatively complex, so that mounting and adjustment are relatively long, which involves equally significant preparation times, particularly for the equipping of multi-spindle and multi-post machines.
CA-A-972 943 also makes known a tool holder for drilling and counterboring which can be rapidly changed, in which the rapid change is made by means of ball bearings which can be positioned so as to release the tool by displacement of a sleeve, but which can in no case achieve a grip on the shank of the tool, as they do not permit sufficient rigidity of mounting.
In fact, such a grip on the shank of the tool by means of the ball bearings of the rapid-change device would be incompatible with a rigid mounting, because adjustment by the screw built into the cage housing the ball bearings would be impossible.
According to this document CA-A-972 943, no device is provided for tightening by traction which would cooperate with a corresponding part of a mobile part. In fact, the tightening screw of the sleeve support of the means of rapid change cannot serve to lock the mobile part after adjustment. This screw thus serves only to hold the support on which is mounted the sleeve permitting rapid mounting and dismounting, and this screw is not in any way designed to grip the shank of the tool, which would become impossible to dismount.
In addition, FR-A-1 595 136 describes an adjustment device in which a means for displacement of the tool on the tool holder is not connected in translation with the body of the tool holder, adjustment being possible only in one direction by a greater or lesser grip of this means on the shank of the tool. The necessary result is a less precise adjustment, especially due to the fact of the total independence of this means of displacement with regard to the tool holder.